Check half-year balance (6)
I believe the answer is:
arrest
'check' is the definition.
(synonyms)
'half-year balance' is the wordplay.
'half' suggests halving the letters.
'balance' becomes 'rest' (I've seen this in another clue).
'year' cut in half is 'ar'.
'ar'+'rest'='ARREST'
(Other definitions for arrest that I've seen before include "Run in" , "Stop - detain" , "Take into custody as police do" , "Stop (on suspicion)" , "Catch" .)